作业帮[3-X Y][3 X Y]
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 12:39:28
解2(x²-xy)-3(2x²-3xy)=(2x²-6x²)+(-2xy+9xy)=-4x²+7xy再问：����|-15|-8�£�-2��+4*�
3xy是3x原式=(x-3y)(x+2y)+3x+y+2十字相乘x-3y2×x+2y1所以原式=(x-3y+2)(x+2y+1)
1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a
3xy[2xy-x(y-2)+x-1]=3xy(2xy-xy+2x+x-1)=3xy(xy+3x-1)=3x^2y^2+9x^2y-3xy
3xy[2xy-x（y-2）+x]＝3xy[2xy-xy+2x+x]=3xy(xy+3x)=3x²y²+9x²y
(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^
5x^2y/-1/2xy*3xy^2=-7.5x²y²
3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2
=xy-3xy+2xy-xy=-xy
-3(2x²-xy)+4(x²+xy-6)=6x²+3xy+4x²+4xy-24=-2x²+7xy-24
2x²-3xy+(2xy-x²)=2x²-3xy+2xy-x²=x²-xy=x(x-y)
-3(2x^2-xy)+4(x^2+xy-6)=-6x^2+3xy+4x^2+4xy-24=-2x^2+7xy-24再问：thankyou~
原式=1-3xy+x+(-4x-6xy)=1-3xy+x-4x-6xy=1-3x-9xy
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
由xy=3，得到x=3y，则原式=9y2+6y2−3y29y2−3y2+y2=127．
3xy-3xy-xy+2yx=-xy+2xy=xy
是同类项同类项的定义为：所含字母相同,并且相同字母的指数也相同的项叫做同类项,所有的常数项都是同类项.3xy和-3xy的字母都是x和y,而且都为1次,所以是同类项.
-1/3(xy+3)^2+3(3-xy)^2=（-1/3）[(xy+3)²-9(3-xy)²]=(-1/3)(xy+3+3(3-xy))(xy+3-3(3-xy))=(-1/3)(
结果为：xy(y+1)(y-1)过程：先提取公因式xy,则原式=xy(y^2-1),然后利用平方差公式可以得到原式=xy(y+1)(y-1)